摘要
[Objective] Surveys of phytoplankton were taken during the autumn of 2009 along Anhui-Jiangsu reaches of the Yangtze River to understand the species com- position and their spatial distributions. [Method] Phytoplankton species, their quanti- ties, biomass and the Mcnaughton＇s dominance indices were all measured and their spatial distribution characteristics were determined using cluster analysis. [Result] There were 27 species, belonging to 5 phyla, namely Chlorophyta, Bacillariophyta, Cyanophyta, Euglenophyta and Cryptophyta, of phytoplankton collected and identified from the surveys. Results showed that Bacillariophyta was the predominant phyto- plankton with 16 species collected which accounted for 59.3% of the total species identified. The number of species collected belonging to Chlorophyta, Cyanophyta, Cryptophyta and Euglenophyta were 6, 2, 2, and 1, accounting for 22.2%, 7.4%, 7.4% and 3.7% of the total number identified, respectively. At the species level, the predominant species were Fragilaria crotonensis, Melosira italica, Navicula crypto- cephala, Cyclotella striata and Chroomonas acuta. Phytoplankton abundance was ranging from 5.68×10^4 to 7.08×10^4 cells/L with its average of 6.01×10^4 cells/L. Phyto- plankton biomass was ranging from 30.43 to 34.73 μg/L with its average of 32.46 μg/L. Compared with the previous reports, the number of phytoplankton species was decreased but its abundance and biomass was increased along the Jiangsu reach of the Yangtze River. However, Bacillariophyta species were still the predominant species and the phytoplankton community structure had not significantly changed from the previous studies. [Conclusion] These results might be explained as that the water quality in the Yangtze River was deteriorated but had not come to the worst. The results of similarity analysis gave two clusters of phytoplankton community as Nanjing, Wuhu and Jiangyin sampling sites were clustered into one group and Tongling and Anqing were clustered into another group.
【目的]为了更好地了解长江安徽-江苏段浮游植物资源现状，并为该江段的生态环境评价和综合开发利用提供一定科学依据。防法1根据种类组成、数量分布、生物量分布以及Mcnaughton优势度指数等多项生物学指标分析浮游植物群落结构，并应用聚类分析法研究长江安徽一江苏段浮游植物空间分布特征。[结果12009年秋季，长江安徽-江苏段共检出绿藻（Chlorophyta）、硅藻（Bacillariophyta）、蓝藻（Cyanophyta）、裸藻（Euglenophyta）、隐藻（Cryptophyta）5门27种；其中，硅藻种数最多，16种，占浮游植物总种数的59．3％；其次是绿藻，6种，占浮游植物总种数的22．2％；之后分别是蓝藻、隐藻、裸藻，分别为2、2、1种，分别占浮游植物总种数的7．4％、7．4％、3．7％；浮游植物优势种为巴豆叶脆杆藻（Fragilariacrotonensis）、意大利直链藻（Melosiraitlica）、隐头舟形藻（Naviculacryptocephala）、小环藻（Cyclotella）以及尖尾兰隐藻（Chroomonasacuta）；长江安徽-江苏段浮游植物数量变化在5．68×10^4-7．08×10^4cells／L，平均为6．01×10^4cells／L，生物量变化在30．43～34．73μg／L，平均为32．46μg／L。[结论1与以往的研究相比，长江江苏段浮游植物种类数减少，数量和生物量上升，说明长江江苏段的水质恶化，但浮游植物群落结构未发生明显变化，仍以硅藻为主要优势种，显示出长江江苏段水质的恶化程度尚不严重。浮游植物相似性聚类分析显示，长江安徽一江苏段的浮游植物群落结构大致聚为2类，南京、芜湖、江阴3站聚为一类，铜陵、安庆站聚为一类。
基金
Supported by Fishery Germplasm Conservation Project of the Ministry of Agriculture(MOA)(No.6115048)
State Specific Project on Fundamental Scientific Research Financed to Public Institutes(No.2009JBFB10)~~
